Lathe accessory.



W. RUPPERT.

LATHE ACCESSORY.

APPLIOATION FILED NOV. 22, 1911.

1,033,943. Patented July 30, 1912.

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COLUMBIA PMNOORAPH CO.,WASHINGTON, D. c.

TINTTE STATES PATENT UFFTQE.

WILHELM RUPPEBT, OF PQRZ-ON-TI-IE-BHINE, GERMANY.

LATHE AGCESSORY. I

osseas.

Application filed November 22, 1911.

To all whom it may concern:

Be it known that I, WILHELM RUPPERT, a citizen of the Empire of Germany,residing at Porz-on-the-Rhine, in the Empire of Germany, have invented anew and useful Lathe Accessory, of which the following is aspecification With ordinary screw cutting lathcs possessing a leadingfeed screw and a two-part sliding nut attached to the saddleit is aftercutting the first chip in forming the thread always necessary to firstwithdraw the cutting tool from the work-piece, then to open the slidingnut for releasing the feed screw and to stop the lathe, afterward torapidly return the saddle to about its initial posi tion and next tocarefully adjust the saddle so as to make sure, that the tool againengages in the work-pieceexactly on the correct place and does notstrike the material on a wrong place. Only after the readjustment of thesaddle the lathe is restarted for cutting the second chip, after whichthe same series of operation is repeated, until the work is finished.The repeated stopping of the lathe is, however, objectionable, asthereby a good deal of time is lost. Only very skilled workmen are ableto perform the operation satisfactorily without stopping the lathe Myinvention relates to a simple accessory, which can be attached to anyordinary lathe having a feed screw without any further alterations andwill enable any unskilled workman to disengage and reengage the saddleeasily and correctly without stopping the lathe,

I will now proceed to describe my invention with reference to theaccompanying drawing, in which Figure 1 is a vertical longitudinalsection through an accessory on the line A-B in Fig. 2. Fig. 2 is anelevation of the same, Fig. 3 is a horizontal section through the lineCD in Fig. 1, Fig. 4 is aside view of a modified accessory, Fig. 5 is ahorizontal section through the line E-F in Fig. 4, and Fig. 6 is aperspective view of a screw-cutting lathe provided with the accessoryshown at Figs. 1 to 3.

Similar letters of reference refer to similar parts throughout theseveral views.

The new accessory essentially comprises a support and a gear wheel. Thesupport consists of an upper horizontal plate a and two verticallyslotted parts I) and c. The

Specification of Letters Patent.

Patented J 1113 30, 1912.

Serial No. 661,838.

upper plate a is connected with the upper part b by means of a screw Zengaging in the lug j and can be turned and displaced with regard to thepart Z). The two parts Z) and 0 can be longitudinally displaced withregard to one another and connected together by means of two bolts n andnuts which pass through the longitudinal slots 7% of the two parts. Avertical preferably exchangeable pin 79 is secured with its lower end inthe arm 70 of the lower part c and on this pin a cylinder 9 is made toturn. An exchangeable gear wheel d can be connected with the cylinder 9and in any known manner be prevented from turning on the cylinder, forexample by means of a small pin. Above the gear wheel d an indicator eis put on, which can be prevented from turning on the pin 3) in anyknown manner, for example by means of a nut 1" engaging in the upperthreaded end of the pin. The gear wheel cl is provided on its uppersurface with several radial lines o 0, over which the indicator? passesduring the rotation of the gear wheel d.

The upper plate a is provided with a slot f and can be fastened on theupper surface of the saddle 9 (Fig. 6) of any screw-cutting lathe h bymeans of a bolt 2' engaging with its head in a dovetail-groove of thesaddle and passing through the slot f. The two parts Z) and 0 of thesupport can be dis placed with regard to one another and so adjusted asto bring the gear wheel cZ intothe horizontal central plane of the feedscrew 2,. The pitch of the gear wheel (Z requires to be equal to that ofthe feed screw 2,, so that the gear wheel can mesh with the feed screw.The size of the gear wheel and consequently its number of teeth isimmaterial, but for practical reasons it is advisable to make the gearwheel neither too large nor too small in diameter. i/Vhen assuming thefeed screw to have an integral number, say two, three, four or five, ofturns to the inch and the gear wheel (Z to have sixty teeth, this numbercan be divided by any of the above numbers of turns without a remainder.As however, for a feed screw having two or three turns to the inch thegear wheel d having sixty teeth would be too large for use, it isadvisable to employ two gear wheels having 2d and teeth for theaccessory, the gear wheel having 2% teeth being used for feed screwswith two or three turns to the inch and the gear wheel having 60 teethfor feed screws with four, five or six turns to the inch. On the gearwheel having 24 teeth every second or third next tooth and on the gearwheel having 60 teeth every fourth or fifth or sixth next tooth ismarked with a radial line 4).

In case the feed screw is made to the metric scale, the number of teethof the gear wheel (1 does not matter much. In such cases the gear wheel(Z is connected with the lower end of the cylinder g, as is shown atFigs. 4 and 5, while the upper end of the cylinder 9 is rigidlyconnected with a disk w, which on its upper surface is provided with amillimetric scale. Then certain of the division lines of this scale arespecially marked, as is for example shown in Fig. 5. Preferably the diskw is provided in its central hole with a pin adapted to engage in arecess of the cylinder 9, so that in this manner the disk is obliged topartake in the revolution of the gear wheel of and can be exchanged foranother one.

When commencing with the screw-cutting, the indicator 6 is first placedover any of the radial lines o in the case of Figs. 1 to 3 or over anyof the marked division lines in the case .of Figs. 4 and 5. During theforward motion of the saddle 9 along the lathe bed the gear wheel willremain immovable, but when at the end of the stroke the sliding nut isopened, so that the saddle 9 stops and the feed screw 6 continuesturning, of course by reason of the gear wheel meshing with the feedscrew the former will be set to slowly rotate, so that the respectiveradial line 0) or marked division line leaves the indicator 6. 'When nowthe saddle is rapidly returned to approximately its inisame time to movethe tool forward by means of the cross slide, when the point of the toolwill strike the work-piece exactly turns to the inch of the feed screw,for ex-.

ample two, three or four, it is unnecessary to wait for the moment atwhich the indicator e covers a certain one of the several radial lines22, but the indicator may cover any of them.

I claim:

1. In a screw-cutting lathe having a feed screw, the combination with aslotted plate adapted to be adjusted on the saddle, a pendent postconnected with said plate and having a vertical slot, a verticallyslotted support, bolts passing through the slots of said post and saidsupport for connect-ing together these parts, said support having ahorizontal arm, a vertical pin secured in said arm, a gear wheelturnable on said pin and adapted to mesh with the feed screw andprovided on its upper surface with division lines, and an indicatorfastened on said pin above the division lines of said gear Wheel. I

2. In a screw-cutting lathe having a feed screw, the combination with aslotted plate adapted to be fastened on the saddle, a pendent postconnected with said plate and having a vertical slot, a verticallyslotted support, bolts passing through the slots of said post and saidsupport for connecting together these parts, said support having ahorizontal arm, a vertical pin secured in said arm, a gear wheelturnable on said pin and adapted to mesh with the feed screw, a diskabove said gear wheel and connected therewith and having on its uppersurface division lines, and an indicator fastened on said pin above thedivision lines of said disk.

l/VILI-IELM RUPPERT.

'Witnesses':

JOSEPH STODTEN, CARL SIEGREN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G. v

